Illness duration and symptom profile in a large cohort of symptomatic UK school-aged children tested for SARS-CoV-2

BackgroundIn children, SARS-CoV-2 is usually asymptomatic or causes a mild illness of short duration. Persistent illness has been reported; however, its prevalence and characteristics are unclear. We aimed to determine illness duration and characteristics in symptomatic UK school-aged children tested for SARS-CoV-2 using data from the COVID Symptom Study, the largest citizen participatory epidemiological study to date. MethodsData from 258,790 children aged 5-17 years were reported by an adult proxy between 24 March 2020 and 22 February 2021. Illness duration and symptom profiles were analysed for all children testing positive for SARS-CoV-2 for whom illness duration could be determined, considered overall and within younger (5-11 years) and older (12-17 years) age groups. Data from symptomatic children testing negative for SARS-CoV-2, matched 1:1 for age, gender, and week of testing, were also assessed. Findings1,734 children (588 younger children, 1,146 older children) had a positive SARS-CoV-2 test result and calculable duration of illness within the study time frame. The commonest symptoms were headache (62.2%) and fatigue (55.0%). Median illness duration was six days (vs. three days in children testing negative), and was positively associated with age (rs 0.19, p<1.e-4) with median duration of seven days in older vs. five days in younger children. Seventy-seven (4.4%) children had illness duration [≥]28 days (LC28), more commonly experienced by older vs. younger children (59 (5.1%) vs. 18 (3.1%), p=0.046). The commonest symptoms experienced by these children were fatigue (84%), headache (80%) and anosmia (80%); however, by day 28 the median symptom burden was two. Only 25 (1.8%) of 1,379 children experienced symptoms for [≥]56 days. Few children (15 children, 0.9%) in the negatively-tested cohort experienced prolonged symptom duration; however, these children experienced greater symptom burden (both throughout their illness and at day 28) than children positive for SARS-CoV-2. InterpretationSome children with COVID-19 experience prolonged illness duration. Reassuringly, symptom burden in these children did not increase with time, and most recovered by day 56. Some children who tested negative for SARS-CoV-2 also had persistent and burdensome illness. A holistic approach for all children with persistent illness during the pandemic is required. FundingEngineering and Physical Sciences Research Council (EPSRC), National Institute for Health Research (NIHR), Medical Research Council (MRC), Zoe Global Limited, The Wellcome Trust, Alzheimers Society. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSSARS-CoV-2 in children is usually asymptomatic or manifests as a mild illness of short duration. However, anecdotal cases have raised concerns of prolonged illness in children, with no clear resolution of symptoms several weeks after onset, as is observed in some adults. How common this might be in children, the clinical features of such prolonged illness in children, and how it might compare with illnesses from other respiratory viruses (and with general population prevalence of these symptoms) is unclear. Added value of this studyWe provide systematic description of COVID-19 in school-aged children. Our data, collected in a digital surveillance platform through one of the largest citizen science initiatives, show that long illness duration after SARS-CoV-2 infection in school-aged children does occur, but is uncommon. Only a small proportion of children have illness beyond four weeks; and the symptom burden in these children usually decreases over time. Most children resolve all symptoms by eight weeks, providing reassurance about long term outcomes. Importantly, symptom burden does not outnumber that observed in long illness due to causes other than SARS-CoV-2 infection. Implications of all the available evidenceOur results confirm that COVID-19 illness in children and adolescents is resolved in the community, after short duration, low symptom burden and with no need of hospitalization in most cases. Our findings also highlight that allocation of appropriate resources will be necessary for any child with prolonged illness, whether due to SARS-CoV-2 infection or other illness. Our study provides timely and critical data to inform discussions around the impact and implications of the pandemic on UK paediatric healthcare resource allocation.